Problem building project

10 April 2018 19:15
Hello again:
Every time I try to build my projects what I get is:

Traceback (most recent call last):
File "C:\Program Files\Blender Foundation\blend4web_ce\apps_dev\", line 44, in, base_dir)
File "C:\Program Files\Blender Foundation\blend4web_ce\scripts\lib\", line 278, in run
run_build(args[1:], proj_path)
File "C:\Program Files\Blender Foundation\blend4web_ce\scripts\lib\", line 1504, in run_build
build_app(app, **params)
File "C:\Program Files\Blender Foundation\blend4web_ce\scripts\lib\", line 1705, in build_app
File "C:\Program Files\Blender Foundation\blend4web_ce\scripts\lib\", line 1837, in build_html
tmp.append(line[0:engine_pos[1]] + engine_str + line[engine_pos[1]:])
UnboundLocalError: local variable 'engine_str' referenced before assignment

The project info is:

Project Name

Project Title
Mits Logo

Project Author / Company
Mits Soft

Project Icon
[detected automatically]

Application Type

6 Mb

Project Path (Development Directory)

Project Config

Build Directory

Blend Directory(s)

Assets Directory(s)

URL Params
JavaScript Obfuscation Level

JS Compilation Pass-Through List
CSS Compilation Pass-Through List
Build Ignore List
Deployment Assets Directory

Deployment Assets URL Prefix

Deployment Ignore List

My system is Windows 7 64.

Any idea about this problem?

Thank you in advance.
10 April 2018 19:39

Even when I create a new project and try to build it as a compiled project it gives me the same output.

I have found that when I go to the blend4web folder and do a npm list, there are a couple of node modules that appear as extraneous:

npm ERR! extraneous: amcharts3@3.21.12 C:\Program Files\Blender Foundation\blend4web_ce\node_modules\amcharts3
npm ERR! extraneous: rollup@0.50.1 C:\Program Files\Blender Foundation\blend4web_ce\node_modules\rollup

When I try to install them npm gives me an error about executing the install as root, which I can't do as I am in windows. I don't know if this is the problem that keeps me from building the project.
10 April 2018 20:28
Well, I have been able to install the extraneous packages. It was my fault, I had opened the console from the contextual menu and I was not an admin. Opening the console as admin allowed me to install the modules, but when I run the build it still reports the same error:

UnboundLocalError: local variable 'engine_str' referenced before assignment
11 April 2018 12:06
What version of Blend4Web SDK do you use?
Could you show how scripts are linked in your html?
Alexander (Blend4Web Team)
12 April 2018 01:20
Hi, Alexander:
The version of the SDK is 17.12.0
This is my html:
<!DOCTYPE html>


<title>Mits Logo</title>

<meta charset="utf-8">
<meta name="viewport" content="initial-scale=1.0, user-scalable=no, width=device-width">

<link rel="stylesheet" href="mits_logo.css" type="text/css">

<script type="text/javascript" src="..\..\dist\b4w.js"></script>

<script type="text/javascript" src="mits_logo.js"></script>


<div style="width:100%;display:block;">
  <div id="main_canvas_container"></div>


I have attached the project folder, too, if you want to take a look.

Thank you for the response
12 April 2018 10:48
Try to replace 'src="..\..\dist\b4w.js"' with src="../../dist/b4w.js". There is a bug on Windows with backslashes.
Alexander (Blend4Web Team)
12 April 2018 12:16
Ah, ok, I see. I'll try that.

Thank you
12 April 2018 12:27
Well, I have changed that line and still doesn't work. Same error as above.

Do I have to have installed a particular version of python or java or anything? I have python 3.6.2 and Java 8 Update 121 (64bit). I can't remember if they are a requirement…
16 April 2018 15:14
Python comes with Blender and java we have in our SDK. There are no additional requirements.
Trying to reproduce your problem..
Alexander (Blend4Web Team)
16 April 2018 21:21
Managed to reproduce. It seems that this happens only for projects with compile type.
The fix is attached. Could you check?
Alexander (Blend4Web Team)
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